script.js

let name = document.getElementById("name");
let age = document.getElementById("age");
let email = document.getElementById("email");
let number = document.getElementById("number");
let password = document.getElementById("password");
let confirm_password = document.getElementById("confirm-password");

function submit_data() {
    if (check_validation()) {
        save_data();

        name.value = "";
        age.value = "";
        email.value = "";
        number.value = "";
        password.value = "";
        confirm_password.value = "";

        alert("You Are Now Registered!");
    }
}

function check_validation() {
    let name_pattern = /^(?=.{3,20}$)[A-Za-z]+([ '-][A-Za-z]+)*$/;
    let age_pattern = /^[1-9]?[1-9]$/;
    let email_pattern = /^[a-zA-Z0-9.]+@[a-zA-Z\d.-]+\.[a-zA-Z]{2,}$/;
    let number_pattern = /^[6-9]\d{9}$/;
    let password_pattern = /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@#$%^&+=!])[\S]{8,}$/;

    let name_validation = name_pattern.test(name.value);
    let age_validation = age_pattern.test(age.value);
    let email_validation = email_pattern.test(email.value);
    let number_validation = number_pattern.test(number.value);
    let password_validation = password_pattern.test(password.value);

    if (name.value === "") {
        alert("Please Enter Your Name!");
        return false;
    }
    else if (!name_validation) {
        alert("Name Is Not Valid!");
        return false;
    }

    if (age.value == "") {
        alert("Please Enter Your Age!");
        return false;
    }
    else if (!age_validation) {
        alert("Age Is Not Valid!");
        return false;
    }

    if (email.value == "") {
        alert("Please Enter Your E-Mail!");
        return false;
    }
    else if (!email_validation) {
        alert("E-Mail Is Not Valid!");
        return false;
    }

    if (number.value == "") {
        alert("Please Enter Your Number!");
        return false;
    }
    else if (!number_validation) {
        alert("Number Is Not Valid!");
        return false;
    }

    if (password.value == "") {
        alert("Please Enter Your Password!");
        return false;
    }
    else if (!password_validation) {
        alert("Password Is Not Valid!");
        return false;
    }

    if (confirm_password.value == "") {
        alert("Please Enter Your Confirm Password!");
        return false;
    }
    else if (confirm_password.value != password.value) {
        alert("Confirm Password Is Not Same As Password!");
        return false;
    }

    return true;
}

function save_data() {
    let get_data = JSON.parse(localStorage.getItem("user")) || [];

    let collect_data = {};
    collect_data.name = name.value;
    collect_data.age = age.value;
    collect_data.email = email.value;
    collect_data.number = number.value;
    collect_data.password = password.value;
    collect_data.confirm_password = confirm_password.value;

    get_data.push(collect_data);

    localStorage.setItem("user", JSON.stringify(get_data));
}